Zugl.: Diss. Rechts- und Wirtschaftswiss. Fak. Univ. Bern, 1996.

Stuttgart, Univ., Studienarb., 2000.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Sept. 11, 2007). PDF text: x, 138 p. : ill. UMI publication number: AAT 3252820. Includes bibliographical references. Also available in microfilm and microfiche formats.

No description available.

No description available.

The Internet is an essential resource to an ever-increasing number of businesses and home users. Internet access is increasing dramatically and hence, the need for efficient and effective Web server systems is on the rise. These systems are information engines that are accessed through the Internet by a rapidly growing client base. These systems are expected to provide good performance and high availability to the end user. They are also resilient to failures at both the hardware and software levels. These characteristics make them suitable for servicing the present and future information demands of the end consumer. In recent years, researchers have concentrated on taxonomies of scalable Web server system architectures, and routing and dispatching algorithms for request distribution. However, they have not focused on the classification of commercial products and prototypes, which would be of use to business professionals and software architects. Such a classification would help in selecting appropriate products from the market, based on product characteristics, and designing new products with different combinations of server architectures and dispatching algorithms. Currently, dispatching algorithms are classified as content-blind, content-aware, and Domain Name Server (DNS) scheduling. These classifications are extended, and organized under one tree structure in this thesis. With the help of this extension, this thesis develops a unified product-based taxonomy that identifies product capabilities by relating them to a classification of scalable Web server systems and to the extended taxonomy of dispatching algorithms. As part of a detailed analysis of Web server systems, generic queuing models, which consist of a dispatcher unit and a Web server unit are built. Some performance metrics, such as throughput, server performance, mean queue size, mean waiting time, mean service time and mean response time of these generic queuing models are measured for evaluation. Finally, the correctness of generic queuing models are evaluated with the help of theoretical and simulation analysis. / May 2005

Web servers that generate dynamic content are widely used in the development of Internet applications. With the Internet highly connected to people’s lifestyles, the service requirements of Internet applications have increased significantly. This increasing trend intensifies the need to improve server performance in dynamic content generation. In this thesis, we describe the opportunity to improve server performance by co-locating the web server and the application server on the same machine. We identify related work and discuss their respective advantages and deficiencies. We then introduce and explain our technique that passes the client socket’s file descriptor from the web server process to the application server. This allows the application server to reply to the client directly, reducing the amount of data copied and improving server performance. Experiments were designed to evaluate the performance of this technique and provide a detailed analysis of processor time and data copying during response delivery. A performance comparison against alternative approaches has been performed. We analyze the results to understand factors in data copying efficiency and determine that cache misses are an important factor in server performance. There are four major contributions in this thesis. First, we show that in multiprocessor environments, co-locating web servers and application servers can take advantage of faster communication. Second, we introduce a new technique that reduces the amount of data copied by two-thirds. This technique requires no modifications to the application server code (other existing techniques do), and it is also applicable in a variety of systems, allowing easy adoption in production environments. Third, we provide a performance comparison against other approaches and raise questions regarding data copying efficiency. Our technique attains an average peak throughput of 1.27 times the FastCGI with Unix domain sockets in both uniprocessor and multiprocessor environments. Finally, our analysis on the effect of cache misses on server performance provides valuable insights into why these benefits are obtained.

The popularity of the World Wide Web (WWW) in providing a vast array of information has drawn a large number of users in the past few years. The dramatic increase in the number of Internet users, however, has brought undesirable impacts on users, such as long response time and service unavailability. The utilization of multiple servers can be used to reduce adverse impacts. The challenge is to identify a good resource site to allocate to the user given a group of servers from which to select. In this project, a performance-directed site selection system was developed for a web-based application called AADMLSS (African American Distributed Multiple Learning Styles System). Four different sets of experiments were conducted in this study. In order to evaluate the effectiveness of the test system, two other server selection methods, Load-based and Random-based methods, were implemented for comparative purposes. The experiments were also run during daytime and nighttime to see the impact of network load on the response time. Experimental results indicate that the performance-directed site selection system outperforms the Load-based and Random-based methods consistently. The response time is typically high during daytime and low during nighttime, indicating that the network load has an impact on the response time delivered. The results also show that server performance contributes to the overall response time, and network performance is the more dominating factor in determining a good resource site for the user.

Web servers that generate dynamic content are widely used in the development of Internet applications. With the Internet highly connected to people’s lifestyles, the service requirements of Internet applications have increased significantly. This increasing trend intensifies the need to improve server performance in dynamic content generation. In this thesis, we describe the opportunity to improve server performance by co-locating the web server and the application server on the same machine. We identify related work and discuss their respective advantages and deficiencies. We then introduce and explain our technique that passes the client socket’s file descriptor from the web server process to the application server. This allows the application server to reply to the client directly, reducing the amount of data copied and improving server performance. Experiments were designed to evaluate the performance of this technique and provide a detailed analysis of processor time and data copying during response delivery. A performance comparison against alternative approaches has been performed. We analyze the results to understand factors in data copying efficiency and determine that cache misses are an important factor in server performance. There are four major contributions in this thesis. First, we show that in multiprocessor environments, co-locating web servers and application servers can take advantage of faster communication. Second, we introduce a new technique that reduces the amount of data copied by two-thirds. This technique requires no modifications to the application server code (other existing techniques do), and it is also applicable in a variety of systems, allowing easy adoption in production environments. Third, we provide a performance comparison against other approaches and raise questions regarding data copying efficiency. Our technique attains an average peak throughput of 1.27 times the FastCGI with Unix domain sockets in both uniprocessor and multiprocessor environments. Finally, our analysis on the effect of cache misses on server performance provides valuable insights into why these benefits are obtained.

The Internet is an essential resource to an ever-increasing number of businesses and home users. Internet access is increasing dramatically and hence, the need for efficient and effective Web server systems is on the rise. These systems are information engines that are accessed through the Internet by a rapidly growing client base. These systems are expected to provide good performance and high availability to the end user. They are also resilient to failures at both the hardware and software levels. These characteristics make them suitable for servicing the present and future information demands of the end consumer. In recent years, researchers have concentrated on taxonomies of scalable Web server system architectures, and routing and dispatching algorithms for request distribution. However, they have not focused on the classification of commercial products and prototypes, which would be of use to business professionals and software architects. Such a classification would help in selecting appropriate products from the market, based on product characteristics, and designing new products with different combinations of server architectures and dispatching algorithms. Currently, dispatching algorithms are classified as content-blind, content-aware, and Domain Name Server (DNS) scheduling. These classifications are extended, and organized under one tree structure in this thesis. With the help of this extension, this thesis develops a unified product-based taxonomy that identifies product capabilities by relating them to a classification of scalable Web server systems and to the extended taxonomy of dispatching algorithms. As part of a detailed analysis of Web server systems, generic queuing models, which consist of a dispatcher unit and a Web server unit are built. Some performance metrics, such as throughput, server performance, mean queue size, mean waiting time, mean service time and mean response time of these generic queuing models are measured for evaluation. Finally, the correctness of generic queuing models are evaluated with the help of theoretical and simulation analysis.